The Third Wheel
by bsloths
Summary: Emily discovers a secret about Derek that might have serious consequences for their relationship. Oneshot. Demily with a Dasey slant.


Today is my two-year anniversary as a writer on ffnet. Forty-two stories, some great friends, and lots of self-esteem - our fandom is amazing.

Happy birthday, TheBucketWoman! You've been with me since just about the beginning. I was so excited when you reviewed me for the first time. I definitely befriended a rock star that day, and you've been nothing but encouraging and sweet and funny since. You're the best!

And now, the fic. Just a little post-_Futuritis_, presumably pre-_Vacation with Derek_ glimpse of Dasey: my version of the (inevitable) Demily breakup. Enjoy!

--Brandi

Disclaimer: It's Daphne's world. I just play in it. (And capitalize non-monetarily on the glaringly obvious stepcestual subtext.)

**The Third Wheel**

It was now or never.

"When did you know?"

"Hmm?"

Emily stopped stroking Derek's hair and pushed him up off of her lap.

"When did you know," she took a deep breath, "that you were in love with her?"

Derek raised his eyebrows. He didn't say anything, just stared into Emily's eyes, possibly trying to gauge how much she knew. She had been right to catch him off guard like that, when he was nice and relaxed. So far, it was working to her advantage.

"I'm in love with who now?" he finally shot back, satisfied grin on his face. She knew he was trying to make her question seem utterly ridiculous.

"My best friend." She couldn't quite bring herself to say Casey's name.

Derek's face fell, and just like that, she had won. He was trapped.

"I think it's time for Derek to be getting home now," Emily's father called as he entered the living room. He always did have impeccable timing.

"Yeah, uh, good night Mr. Davis, Emily." Derek was off the couch and out the door before Emily could recover enough to respond.

"You okay, Em?" her father asked when he saw her frown.

"Yeah. I'm fine, Dad. Just tired." She faked a yawn and stood up. "I'm going to bed."

Upstairs, Emily flicked on her bedroom light and stared glumly at the house next door. The lights seemed to be off. It was too late to call Casey.

Not that she could really talk to Casey about this, anyway. 'By the way, Case, your brother, the guy I'm dating, is in love with you, and I just found out' was not exactly something she'd want to hear.

Emily was pretty sure that Derek was still mildly repulsive to Casey. Denial was not a good color on her.

Ever since Emily had started dating Derek, things had been different with Casey. They were still close, but now they couldn't say certain things to each other. Casey no longer complained to her about Derek, which left her with very little to say sometimes. Emily was afraid to talk about Derek at all, even though sometimes he was all she wanted to talk about.

This was why Sam and Casey didn't work out, she reasoned. You can't date your friends' siblings.

But apparently, "sibling" had become a very loose definition of what Casey and Derek were to each other.

She had always sensed their connection. She knew that they had _fun _fighting, though neither would admit it. She just thought that was what normal brothers and sisters did. She was more of a second mother to Dimi, since he was so much younger. And the Shleppers weren't exactly a typical family. She had no idea how siblings that close in age were _supposed_ to act.

Prom night had raised her suspicions. Derek had been determined to make Emily his girlfriend in front of Casey, and the fact that Casey thought he was asking her permission made Emily pause. She knew something was up. It hadn't made sense to her then that Derek would want to make Casey jealous.

She had been over Derek for awhile. But to all of a sudden have him reciprocate her feelings was a dream come true – she couldn't pass up the opportunity to date him. And she didn't regret it. He was a great guy. But…she knew it wasn't going to last. They didn't have enough in common, and there just wasn't enough, well, _heat_.

She had no doubt that Derek genuinely liked her. But it was obvious that Casey would always come first. When she dumped Truman for the second time two days after graduation, and called Derek in tears, Derek had left Emily, her shirt halfway unbuttoned, to go pick up Casey from Smelly Nelly's. It kind of screwed with her self-esteem a little bit when he did things like that.

But she shook it off. In some ways, Derek was still the immature boy he had always been. He wasn't that perceptive when it came to stuff like feelings. So she was sure that he hadn't meant to abandon her. And when he didn't call that night, she figured Casey was still making everyone miserable. Sure enough, Emily got a call from her friend, and spent the rest of the night consoling Casey. According to her, Derek had treated Casey to dinner and then brought her home. She couldn't believe how nice he had been to her. _Emily_ believed it, but then again, she was dating him. She knew he could be a sweetheart when he wanted to be.

There was the key phrase: when he _wanted_ to be.

It was the next day when everything clicked for her. Derek had brought Casey along to her house for a swim. He kissed Emily hello, and Emily's eyes flickered to Casey, who was biting her lip and looking away. That was weird – Derek didn't usually do PDA.

Emily was already in her suit. She admired the view as Derek stripped off his t-shirt and jumped into the water. He surfaced, brushed the hair out of his eyes, and came to rest his elbows against the edge of the pool.

"Do I have to swim all by myself?" he asked, smirking at Emily in that way that made her melt. There was a reason she had crushed on that boy for _years_.

"Please try to remember that this isn't a date," Casey said sharply. Derek turned his smirk on her. But Casey didn't melt. She stared back at him, jaw set.

Emily felt like it was something she shouldn't interrupt. She had never really paid attention to the way they looked at each other before, but now that she did, she remembered other times when their locked eyes had intimidated her. She had always brushed off the feeling before.

"We'll behave, Case," Emily finally interjected, growing increasingly uncomfortable.

Casey blinked, as if she had forgotten Emily was there. "Oh, I know _you_ will. It's Derek who has no self-control."

Derek splashed water at her, but she was too far away from the edge of the pool for it to reach her.

Emily rolled her eyes. "Come on, Case. Let's not turn this into a fight." She felt as though she was admonishing Dimi for something, instead of trying to make her best friend feel better. Why did those two turn into children around each other?

"You're right. Sorry." Casey smiled at Emily as she stepped out of her flip-flops.

Emily wasn't sure what made her look at Derek just then (women's intuition, maybe?) but as Casey pulled her sundress over her head to reveal a classy two-piece, Emily watched as Derek took her in, eyes roaming over her inappropriately. It was the kind of look that would have made Emily go weak at the knees, had it been directed at her. Even Sheldon had perfected that smoldering stare that said, "I want you." It got Emily every time. But this time, it wasn't directed at her. It only lasted a few seconds, but the force of it hit Emily and made her tingle all the way down to her toes. Why couldn't Derek look at _her_ like that? As Casey finished getting the dress over her head and beckoned Emily into the water, she saw Derek turn his head away and sigh. It was a blink-and-you'll-miss-it moment, but Emily had been paying close attention.

It was completely unnerving. _Why_ had he checked out Casey? That couldn't be normal.

"You coming in the water, Em?" Casey asked, scrunching up her nose at Emily's jittery expression.

"Of course," she smiled as she grabbed Casey's hand, and they jumped in together.

For the rest of the day, Emily kept her eye out for any more weird behavior from Derek. But there was none. They played volleyball and splashed around, and when Marti and Dimi came outside to join them, Derek turned into a big kid and barely even looked at Casey and Emily while they played.

When everyone left for the day, Emily called Sam. She needed to figure some things out.

"Hey Emily. What's up?"

"Hey Sam. I have a weird question to ask you."

"Shoot." She knew Sam would be helpful. He was good about this kind of stuff.

"Is it normal for Derek to check out girls when he's in a relationship?"

Sam laughed, but not in a mean way. "Emily, you've _met_ Derek, right?"

Emily laughed, too. "I guess I'm being silly. So you're saying I have nothing to worry about."

"Of course not. I don't think he's going to change, Em. He really does like you, though."

"You think so?"

"Yes. Checking out random girls is like a sport to Derek. You're the one he wants."

Emily shook her head, and then realized Sam couldn't see her. She was fairly certain that she wasn't the _only_ one he wanted. "It, um, _wasn't_ a random girl."

"Oh, really?" Sam failed miserably at sounding nonchalant.

"You know something!" Emily cried. It would make sense that Sam would pick up on those vibes. After all, he wasn't dating Derek. Sam wasn't blinded by his charm.

"No, I don't." Sam's voice squeaked.

"Oh, Sammy," Emily sighed.

"Tell me what you think you know," Sam said, recovering from being put on the spot.

"Derek and Casey came over to swim today," she began, suddenly nervous to tell him the truth. What if she really _was_ overreacting? "And Derek definitely checked Casey out as she took off her clothes."

"You sure?"

"I'm sure. Believe me, I'm sure. And it's not the first time I've noticed something weird."

"Ah," Sam said knowingly. "The touching, the getting in each other's faces, the shameless flirting…"

"Flirting? No, they don't flirt!"

Sam sighed. "Of course they do. '_Der-ek_! Why did you steal all my clothes? Now I have to wear your stinky boy stuff'," he whined in a pretty good Casey imitation.

Emily realized Sam was right. Banter like that was their version of flirtation. "Spacey, I bet you can't go one night without doing homework. You keeners are all such freaks," she fired back in a terrible Derek impersonation.

"You're not going out with Sam. I forbid it. You've heard of the male code that I totally just made up, right?" Sam-as-Derek snarked.

Emily continued to play along, this time imitating Casey. "You're not going out with Emily. I make it my business to know everything about you, and she's not your type!"

"I'm going to stare at you until you back down."

"Well you're going to be staring at me for the rest of your _life_ because I _never_ back down."

Emily dissolved into a fit of giggles and Sam chuckled along with her. "I can't believe I was so blind!" she crowed. "Three years! Three years as Casey's best friend! And, like, ten of crushing on Derek!"

"It's okay, Emily. Took me awhile, too. But once Casey and I broke up, I realized how ridiculously obvious Derek can be about it."

Emily stopped laughing. "You think it's only Derek?"

"Well, I think Derek knows how he feels, but is afraid of those feelings. This _is_ Derek we're talking about. Casey is so determined to hate him that she can't see anything else. She's in deep denial."

"So what you said before, about Derek liking me, was a lie?"

She couldn't see, but she was sure Sam was shaking his head emphatically. "No, no. He _does_ like you. But…how can I put this nicely…"

"Don't worry about it. I want to know!"

"Okay. I don't think he sees any kind of future with you. You're the perfect cover. He gets to hang out with you, because he enjoys your company. He gets to bug Casey by dating you, because he knows she hates it. And you're both leaving for university soon, so he doesn't have to feel tied down."

"Wow." Emily's heart was beating incredibly fast. As blunt as Sam's words were, she suddenly had a feeling in the pit of her stomach that every bit was true.

"Sorry, Em."

"No, no, it's okay. Really. This is just a lot of information to take in at once."

"I know. But now it's going to drive you crazy. You're going to see every little touch, every look that lasts too long, and it's going to make you want to scream, because you can't say anything."

"Maybe _you_ can't say something, but I can."

"You shouldn't, Em."

"Why not?"

"Because Derek's been thinking this whole time that he's got everyone fooled. To tell him that he's wrong will not only embarrass him beyond belief, it'll do a number on his pride."

Emily rolled her eyes. "You boys are so weird."

"I know. But trust me, you girls can be weird, too."

Emily snorted. "So, I can't say anything. Fine. Are they just going to keep going on like this?"

"No idea. But it's really none of our business."

"Wait a minute. It's _my_ business! I'm _dating_ one of them!"

"Oh. Yeah. Forgot about that part."

"Yeah."

Sam was quiet for a moment. Emily waited patiently. Finally, he shared, "Look, you do what you think is right. Break up with him if you want, stay with him if you want. I honestly have no idea how this thing is going to play out, so you should do what makes you happy."

"I'm not sure yet what I want to do. I have to think about it."

"I understand."

"Hey, do you think it's weird that they're, you know, stepsiblings?"

Sam made a noncommittal sound. "Derek did introduce her to me as a 'recent accident by marriage.' I think that's the attitude we have to take, you know? They didn't plan to become stepsiblings. I don't think Mr. and Mrs. Venturi decided to get married based on whether or not their children might possibly fall in love."

"That's true. It's not their fault." Emily let out a heavy sigh. "Now that I think about it, they really do make sense together. I hope they figure that out."

"Me, too."

"Well, I have to think about all this. Thanks, Sam."

"I'm sorry you found out that way. And that I had to tell you some things you probably didn't want to hear."

"No, I'm glad you did. Really."

"Good. I'm here if you need to talk."

"Yeah, same here, if you need to."

"Thanks."

"Bye, Sam."

"Bye, Emily."

They hung up, and Emily flopped down onto her bed.

Strangely enough, she wasn't upset. A little on edge, of course, but that wasn't how you were supposed to feel when you found out something like this. You were supposed to be angry, and hurt, and confused…

Scratch that. She _was_ confused.

Maybe she really was over Derek for good. He was a great boyfriend, but Sam was right. Who were they kidding? Their relationship was not going to last. And they were going to different universities in a couple of months, like Sam said. Emily was slightly saddened that their effort hadn't really worked out, but overall, she was okay. They could always try to stay friends.

That was why she decided to go ahead and call Derek on his emotional cheating when he came over the next night. She deserved to spend her summer having fun with her friends, not stuck in a relationship neither party really wanted to be in anyway.

She had been hoping to get a little farther that night than just admitting she knew about his feelings for Casey. Figures her dad had to interrupt them and ruin it.

She would just have to try again tomorrow.

&&&

"Hey Case, what's Derek's favorite breakfast food?"

Emily should have known this. Luckily, she was positive that Casey did.

"Chocolate chip pancakes with chocolate syrup. Why?"

Emily noticed her wary tone, but decided to ignore it. "Nothing important. Is he awake yet?"

Now Casey sounded even more hesitant. "Of course not. It's not even ten yet."

Any other day, Emily wouldn't have heard the hint of affection in her response. But it was there, whether Casey realized it or not.

"I'll be right over."

Emily gathered the supplies she needed and headed next door.

"Mind if I use your kitchen?" she asked after exchanging greetings with Casey.

"Go right ahead. But what's this about?"

Emily shrugged. "I thought you didn't like to hear about my relationship with Derek."

"Oh." Casey winced. "Well, as your best friend, I can make an exception."

"I was hoping you'd say that. Because I'm breaking up with him."

"You are?" Emily felt a stab of annoyance at the delight in Casey's eyes and the way the corners of her mouth turned up slightly.

"Some best friend." She didn't blame Casey for being happy, but really, it was common courtesy to at least _act_ sympathetic. Jeez.

"Sorry, Em."

"Yeah, whatever."

Casey looked stricken. "I shouldn't have reacted that way. Let me try again." She wiped the smile off her face, and this time she seemed sincere. "I _am_ sorry you're breaking up."

"No, you're not, actually, and that's okay," Emily sighed.

"Em, are you sure? I _do_ want you to be happy."

"Just not with Derek."

"Exactly."

The friends smiled at each other. Emily was relieved. The breakup would change their relationship again, back to the way it should be.

By the time Casey and Emily were finished with the pancakes, the rest of the family was up and hoping for handouts. Emily made sure to save a stack for Derek, but otherwise let the McDonald-Venturis go to town.

"What do you need me to do?" Casey asked, as Emily grabbed Derek's plate out of Edwin's reach.

"Just get him down here. I was hoping the smell would wake him up, but I guess he's still asleep. I have a feeling he's going to want to run when he sees me, but I'm hoping the food will make him stay."

"Run? Why?" Casey frowned. "I thought you hadn't broken up with him yet."

Emily was tempted to tell her about the night before, but couldn't do it without revealing too much. "Oh…we sort of had a fight," she said vaguely.

Casey shrugged. "Okay. I'll go knock on his door for you."

She was gone a few minutes, and when she returned, a groggy Derek was trailing behind her.

"What's this I hear about chocolate—" he froze when he saw Emily sitting on the couch, and Casey had to grab his arm and pull him the rest of the way down the stairs. Naturally, he protested the whole way. But, Emily noticed, he wasn't breaking free of Casey's grip. She was pretty sure he was strong enough to. Maybe he just liked having her touching him. Emily's forehead creased. Ugh. This whole situation was going to be quite an adjustment. Sam was right – now she was noticing even the most innocent-seeming gestures.

"I'll take those off your hands," Derek said when he reached the couch, suddenly all smiles again. He smirked at Emily as he grabbed the plate and began shoving the pancakes into his mouth.

"That's right, Derek, eat up," Emily grinned wickedly, and Derek choked.

"You poisoned them, didn't you?" he asked with his mouth full.

Casey laughed, and Derek swallowed. "Nah, I wouldn't put it past Spacey, but _you_, Em?" he eyed her carefully.

"The pancakes are fine. I just want you full and happy for when we…talk." She glared at him pointedly and she could have sworn that fear flashed across his face.

But he just shrugged and mumbled, "Yeah, yeah."

The rest of the family was finishing their breakfast and was trickling out of the kitchen. They all thanked Emily for a great breakfast, and she brushed off the compliments. George looked like he wanted to ask what her motivation for feeding them had been, but then he spotted Derek still working on his plateful and raised his eyebrows at Emily. She turned to Casey and shook her head slightly. Casey took the hint and shooed her family out of the living room.

"Emily and Derek need some privacy," she told them, and Emily mouthed a thank you at her.

Once they were alone, Derek took his time finishing his breakfast.

"Your strategy isn't going to work, you know," Emily told him with a smile. "I'll sit here all day. We _are_ going to talk."

Derek looked at her in surprise. "You're not mad at me?" he asked.

"No. I'm not."

"Shouldn't you be? I mean…last night…" He didn't look like he wanted to relive it.

"I'm not mad. And you know what, Derek? I've decided that you don't even have to tell me anything. What you do on your own time is your business. But when it affects our relationship, I feel like it's my place to say something."

Emily almost felt sorry for him. He looked so lost. He finally settled on, "Wait…huh?"

"Okay. Here it is. Derek, I like you a lot. And I know you like me too. But we're kidding ourselves if we think this relationship is going anywhere. You're not in love with _me_."

Derek seemed like he wanted to deny it, but even he had the sense not to. "So, you're breaking up with me?"

"Yes. I want to go back to being friends. That worked well for us. Do you remember our first date three years ago? I was a giggly mess. I was totally tongue-tied. This time around, it's been different. It's been nice to be able to be myself with you. I'm glad we tried again. But…like I said, we're kidding ourselves. I don't want to be your girlfriend anymore."

Derek flopped back against the couch. "Wow. I can't believe how cool you're being about this."

"I'm just that awesome," Emily agreed, and Derek shook his head. But he was smiling, a real smile.

"The official story is that we just sort of burned out," Derek instructed her. "Nothing about another girl." His smile disappeared, and he suddenly looked nervous.

"No, of _course_ not," she emphasized. "But we tell people that _I_ broke up with _you_. Is that too much of a blow to your pride?" She smartly kept from rolling her eyes.

He sighed. "Fine. I guess I deserve that."

Emily put a hand on Derek's knee and looked deep into his eyes. "And Derek, if you ever need to talk about…you know, your feelings," he made a face, "about that nonexistent other woman," he made another face, "I'm here for you. I mean it." She patted his leg and held his gaze.

She wasn't expecting any sort of response, but he leaned forward and gave her a tight hug. "I'm glad we're friends, Emily," was all he said, but she knew exactly what he meant.

She also knew he would probably never talk about his feelings for Casey with her, but that was okay. He knew that she knew, and that was enough. For now.

&&&

"I'm so glad to have my best friend back," Casey said as she and Emily strolled through the mall later that day.

"Why's that?" Emily asked, powerless to resist Casey's enthusiasm.

"Well, now we can talk about _boys_ again. We're both single and fabulous!"

"It _is_ pretty nice to be single again," Emily agreed.

"Jerk," Casey mumbled, pointing to their left.

None other than Derek, Sam, and Ralph were standing in an alcove, chatting up some girls who were hanging on their every word.

"He doesn't even have the decency to wait _one day_—" she huffed, but Emily cut her off.

"I'm fine, I promise."

Casey didn't look convinced.

"Really. I'm over him. For good."

Casey beamed. "Finally!" She wrapped an arm around Emily's shoulders and led her away from the guys. "Come on. We'll let Derek flirt with his ditzy blonde. That's how it should be. All is right with the world again."

Not quite _all_, Emily thought, watching Casey's eyes wander back to Derek. She looked a little nauseated.

Emily said aloud, "Oh, Case. Dramatic much?" Casey smiled sheepishly, and they continued on their way.


End file.
